In one preferred embodiment, the present invention provides a very compact, low profile, electrically small, efficient antenna capable of producing circularly polarized radiation patterns for the satellite communication (SATCOM) frequencies (250-300 MHz).
The major engineering problem addressed is that the present invention provides sufficiently large right hand circularly polarized (RCP) gain of −0.880 dBi at the UHF frequency of 300 MHz. A RCP gain near −0.8 dBi at this frequency is quite challenging to achieve with electrically small antennas. In addition, this design is very low profile, as it maximum height is 15 mm, and a maximum width of 85.5 mm2, which results in a very electrically small (ka=0.38) circularly polarized antenna.
One previous approach is an antenna design with the same resonant frequency of 300 MHz. While that previous design operates at the same frequency as the present invention, that prior design does not provide circularly polarized radiation patterns which are critical for SATCOM communications. In addition, that prior design is much larger in physical dimensions, with a maximum height of 66.4 mm, and maximum width of 132.8 mm. These dimensions translate to an electrical dimension of (ka=0.43). This physical size is much too large for many portable applications, such as in the Navy and other applications which require portability.
Another previous design has an operational frequency of 1.5754 GHz, with a corresponding electrical size of (ka=0.495). While that previous design is capable of producing circularly polarized radiation patterns, if the physical dimensions were rescaled to work at an operational frequency of 300 MHz, the maximum dimension in width would result in 157.56 mm, with a maximum height of 78.78 mm. These dimensions again, are much too large for many portable applications in the Navy, and other applications which require portability.